So I have been on Zoloft for 10 years now (I started at 9 y/o and am now 19) and it has worked great in treating my severe anxiety disorder. However, I have been taking an exceptionally high dosage for the past 7 years (200mg daily), which apparently increases possible side effects. The thing is that since I have been taking it for so long and I was so young when I started, I have no idea what aspects of my behavior or body functions are the meds or what are just me. I met with my new "adult" doctor last week for the first time and he told me I need to lose weight. I told him I know but I honestly don't know how to or how I keep gaining weight so consistently (I'm not huge, but I am decently chubby). I don't eat much regularly seeing as another medication I take (and have been taking for almost as long) destroys my appetite. He looked at the meds I'm taking and realized it must be from the Zoloft. I said I thought it wasn't considered a weight gain drug. He explained it typically isn't but since most people take 25mg - 100mg, taking 200mg could cause weight gain. So he suggested I try a new drug. This made me nervous because it took forever to find the right medication and dosage that worked, and I prefer being able to function as a normal adult and have an actual life. I'm still nervous, but we decided on Pristiq, a drug a previous psychiatrist recommended if I ever did want to try something else. I start weening off Zoloft and incrementing Pristiq in a month and a half, and I'm nervous. I have no idea what it will change, if it will work, and what it could possibly screw up. I'm curious if anyone here has

1) Taken Zoloft long term and/or in larger dosages that know more about the side effects
2) Taken Pristiq that could tell me how it worked for them/what side effects they experienced
I'm nervous and excited and desperate to know a little bit more about what could happen moving forward. Thank you for the help!

(PS in case it matters, I have been on Adderall for ADD for 7 years, and Lamotrigine for Depression and Mood Disorder traits for almost 3 years)